Kai Ryssdal: Two items now from the immigration files. First, a report from the Pew Hispanic Center this week that the long wave of Mexican immigration to the United States has slowed sharply. Pew says the net inflow -- the number of Mexicans entering the country -- was just about balanced out over the past couple of years by the number of Mexicans leaving.

That's not likely to shift attention away from undocumented immigration, which brings us to item two. Tomorrow, the Supreme Court takes up Arizona's tough immigration law and the question of whether states get to have a say in that has traditionally been federal turf.

Marketplace's Jeff Tyler reports.

Jeff Tyler: The debate over state immigration laws often focuses on civil rights. But more and more, economics is center stage.

Cecillia Wang: I think what’s new and interesting is that business leaders are increasingly speaking out against these laws.

Cecillia Wang is director of the ACLU’s Immigrants’ Rights Project. She says Mississippi flirted with its own immigration bill.

Wang: The bill was effectively killed because the Mississippi Economic Council, which is the state chamber of commerce, stepped forward and publically opposed the law.

But what about the economic interests of taxpayers in states like Arizona? Bob Dane is spokesman for the Federation for American Immigration Reform, which advocates for a tighter border.

Dane is skeptical of farmers who complain that tough immigration laws make it hard to find labor.

Dane: The great myth is that there are jobs that Americans won’t do. And that is simply said by big business looking for the lowest possible wage to pay workers, and that’s typically illegal aliens.

Farmers in Georgia pay up to $16 an hour, but can’t get locals to take the jobs. So says Brian Tolar -- president of the Georgia Agribusiness Council. Last season, he says Georgia’s immigration law scared away foreign farm workers, leaving crops rotting in the fields.

Brian Tolar: If we don’t have the labor, then we can’t produce Georgia-grown. We can’t produce U.S.-grown. We’ll be importing all that stuff from outside the country. And I really don’t think Americans want that.

Cecillia Wang with the ACLU says the Supreme Court needs to consider...

Wang: Whether we want to tolerate a system in which every state can pass its own immigration laws. That creates a patchwork of clashing rules, so that businesses and ordinary people have to figure out what rules apply when they move from one state to another.